Applying Lazear’s jack-of-all-trades theory, we investigate the formation of entrepreneurial skills in two data sets on innovative new firms. Our results suggest that traditional human capital indicators individually have little or no influence on entrepreneurial skills. However, consistent with Lazear’s theory, those entrepreneurs who exhibit a varied set of work experience have higher entrepreneurial skills relevant for starting and growing a firm. This supports the notion that a varied set of work experiences rather than depth of any particular type of experience or education is important for the development of entrepreneurial skills.